The overall objective of this study is to determine if genetic, immunological and clinical variables can be utilized to identify black individuals at risk of developing gestational diabetes mellitus (GDM) and for individuals so affected to predict who will subsequently become an insulin-dependent (IDDM) or non-insulin dependent (NIDDM) diabetic or normal. The subjects are the Alabama black population of Jefferson County who receive prenatal care at one of the eight County Public Health Department operated Clinics. This involves approximately 3,600 black women which represents approximately 78% of all black women who receive prenatal care in the county. We will determine if there is an association of major histocompatibility complex genetic markers HLA-A, B,C,DR,C4,Bf and GLO, restriction fragment length polymorphisms of the insulin gene, presence of pancreatic islet cell antibodies, family history of diabetes, maternal age, maternal weight, baby birth weight and/or parity with incidence cases of GDM in our black population compared to non-GDM cohorts presenting to the same clinic. We will analyze whether these variables can be used to predict those individuals at risk for developing GDM. We will also determine if the above variables can be used to predict those GDM individuals who are at risk for developing IDDM and/or NIDDM or remain normal. The GDM subjects will be followed throughout the course of their pregnancy at UAB's Complications Clinic. Following delivery, these individuals will be followed longitudinally for five years and evaluated yearly for the susequent development of overt diabetes. Several risk factors have been recognized for GDM as well as IDDM and NIDDM. However, there is a paucity of data available with regard to risk factors for GDM in the black population. Moreover, the interrelationship of clinical, immunological and genetic risk factors for onset of GDM or their use to predict who will sugsequently develop overt disease or recover has not been investigated. Thus, there is an opportunity to utilize a well defined population within the Jefferson County area to more clearly understand risk factor for GDM and the subsequent development of IDDM and/or NIDDM. This study should also provide an opportunity to more clearly define the etiological factors of diabetes in general.